Apparatus and method for treating photographic products in a single bath



Nov. 12, 1963 P. A. ROMAN 3,110,595

APPARATUS AND METHOD FOR TREATING PHOTOGRAPHIC 4 PRODUCTS IN A SINGLE BATH Filed March 23, 1959 Fig.2

PIERRE AMEDEE ROMAN INVENTOR.

ATTORNEY United States Patent APPARATUS AND METHGD FOR TREATING PiggTGGRAPHEC PRODUCTS IN A SINGLE Pierre Ameale Roman, Sucy en Brie, Seine-et-Oise,

France, assignor to Eastman Kodak Company, Rochester, N.Y-, a corporation of New Jersey Filed Mar. 23, 1959, Ser. No. 801,129 Claims priority, application France Aug. 13, 1958 2 Claims. (Cl. 96-48) This invention relates generally to processing systems, and more specifically to an improved apparatus and method for processing photographic paper in a single developer-fixer bath;

The use of a single developer-fixer bath or monobath, as it is commonly referred to in the trade, for the processing of photographic paper is well known in the art. In baths of this type there is a constant race between the developer and fixer, the developer attempting to change as much of the exposed crystals of silver chloride as possible into silver before they are entirely removed by the fixer. Although the relative rates of simultaneously occurring development and fixation are not easily controlled and kept constant as the bath becomes exhausted, these baths are finding increased use in office operation for the rapid reproduction of documents. Heretofore, processing of photographic paper with a single bath has had the disadvantage of resulting in a considerable lowering of the contrast of emulsion. In order to limit this loss of contrast, it has been found necessary to use a minimum quantity of sodium thiosulfate which is compatible with complete fixing within the required time. This loss of contrast which is objectionable appears to be due to the interaction of the developer and fixer. Applicants improved process and apparatus for processing photographic paper in a single bath substantially eliminates this objection.

Therefore, one of the primary objects of the present invention is to provide a method for processing photographic papers in a single developer-fixer bath in which the contrast of the photographic paper is improved over the contrast secured when the paper is processed by any prior known type of method.

Another object of this invention is the provision of an improved method for processing photographic paper in a single developer-fixer bath for achieving an improvement in the degree of separation and control of the developing and fixing actions.

Still another object of the invention is to provide an improved method for processing photographic paper in a single developer-fixer bath for obtaining improved contrast under conditions where the normal fixing rate is too rapid, nad reduces the minimum density where the normal fixing rate is too slow.

One more object of the invention is toprovide an improved method for processing photographic paper in a single developer-fixer bath in which the photographic paper is subjected to the action of the bath for a predetermined time interval during which the bath is unagitated, and then to the action of the same bath for a different predetermined time interval during which the bath is agitated.

Still another object of this invention is to provide an improved method for processing photographic paper in a single developer-fixer bath in which the photographic paper is passed through a first zone in which the bath is substantially unagitated and then passed through a second zone in which the bath is agitated.

Another object of the invention is to provide an apparatus for carrying out this new method of processing photographic paper in a single developer-fixer bath and including adjacent hydraulically connected chambers for holding the bath, and means for agitating the bath in one of the chambers without materially agitating the bath in the other chamber.

Objects and advantages other than those set forth above will be apparent from the following description when read in connection with the accompanying drawing, in which:

FIG. 1 is a side elevation view in section showing a preferred embodiment of the processing apparatus of this invention; and

FIG. 2 is a view substantially taken along line 2-2 of FIG. 1.

As shown in the drawings, the processing apparatus comprises a tank 5 having a pair of spaced apart, semicircular side plates 3 joined together by a semi-cylindrical plate 4 forming the bottom of tank 5. The tank 5 is provided with any suitable type of support member shown as legs 6, each formed of angle iron and having one end secured to the bottom of tank 5, and the opposite end secured to any suitable support base by screws 7. The side plates 3 are further connected together by an upper plate 8 secured thereto by welding or any other suitable way. The upper plate 8 has a quarter-cylindrical portion 9 as seen in FIG. 1 spaced apart from and concentric to bottom plate 4, and a substantially vertical planar portion 11 having one end connected to portion 9. The portion9 of plate 8, side plates 3, and bottom plate 4 of tank Scooperate to form a chamber 12 of relatively small capacity. The portion 11 of plate 8, side plates 3, and bottom plate 4 of tank 5 cooperate to form a chamber 13 of relatively large capacity hydraulically connected to chamber 12. An agitating device such as any commercially available vibrator is provided having a rectangularly shaped agitating-element 14 disposed in chamber 13 and connected to a rotatably driven rod 15. The tank 5 is provided with a combination of developer and fixing solution 19 which is distributed throughout the two chambers 12,13;

In the processing of a photographic material shown as a web 16 with this processing machine, the agitating element 14 is initially operated so that the portion of solution 19 which is contained in chamber 13 is continuously agitated without substantially aifecting the turbulence of that portion of solution 19 in chamber 12. The material 16 to be processed is passed by rollers 17 into the substantially unagitated portion of solution 19 contained in chamber 12 where development principally takes place, and then into the agitated portion of solution 19 contained in chamber 13 where fixing takes place and the processing step is carried to completion. The material 16 is removed from tank 5 by rollers 18.

Owing to the restricted volume of chamber 12, the agitation created by agitating element 14 in chamber 13 is not transmitted to that portion of the developer-fixer solution 19 contained in chamber 12. On the other hand, the small capacity of chamber 12 does not adversely affect the development since a silver chloride emulsion or other rapidly developing emulsion is developed completely in the presence of a small quantity of developer because only a small amount thereof is necessary to the swelling of the gelatin.

The time in which the material 16 passes through the machine varies somewhat, depending upon the characteristics of the product to be treated and the conditions of treatment. Under the particular conditions indicated in the following examples, about 30 seconds are required for the processing, and the material reaches chamber 13 of the machine where solution 19 is agitated about 15 seconds after entering chamber 12.

The composition of two developer-fixer solutions 19 n if! which can be used to carry out the invention are given herebelow:

Example 1 G. Sodium carbonate 30 Sodium sulfate 25 Ascorbic acid; 10 l-phenyl-3-pyrazolidone 1 Potassium bromide 1 Sodium thiosulfate 25 5-phenyl-l-mercaptotetrazole 0.050

Water to make 1 liter.

Example 2 Sodium carbonate 50 Sodium sulfate 70 Ascorbic acid l0 1-phenyl-3-pyrazolidone 1 Potassium bromide 3 Sodium thiosulfate 60 S-phenyl-l-mercaptotetrazole 0.200 Water to make 1 liter.

This bath which has a high concentration of sodium thiosulfate, allows treating an increased number of sheets. If the processingis carried on in a machine such as disclosed, in which lutipnjgis agitated in chamber 13, 80- sheets of size 2 1 X 27 cm. can be processed, whereas without agitation, in accordance with the present invention, the number of sheets treated in satisfactory manner would be approximately 50.

In single-bath processing procedures, it is difiicult to adjust development and fixing and to maintain this adjustment in accordance with the depletion of the bath or solution 19. The process of the invention makes it possible to separate more clearly the two operations and consequently to improve the contrast obtained when fixing is too rapid or to improve the purity of the whites when it is too long.

The invention has been described in detail with particular reference to a preferred embodiment thereof, but it will be understood that variations and modifications can be effected within the spiritand scope of the invention as described hereinabove and as defined in the appended claims.

I claim:

l. The method of continuously processing a strip of exposed light sensitive material by developing and fixing the strip in a single monobath solution comprising the steps of:

filling a tank with a monobath solution containing both developing and fixing ingredients in predetermined.

proportions in which the developing action normally predominates, and dividing the solution into first and second well defined, hydraulically connected processing zones having the same predetenmined proportions of ingredients, in which the second zone contains a substantially greater portion of the volume of the solution,

continuously agitating the portion of the solution in the second zone at a controlled rate sufiicient to cause the fixing action of the fixing ingredients to predominate over the developing action of the developing ingredients in the second zone, while the solution in the hydraulically connected first zone remains in a substantially quiescent state wherein the normal predomination of the developing action is retained, and

continuously transporting the exposed strip at a predetermined speed consecutively into and through said first processing zone for development, through the hydraulic connection, and then into and through said second processing zone for fixing.

2. In a processing machine having a monobath solution containing both developing and fixing ingredients, the combination comprising: a tank for said monobath solution comprising side plates connected by a semi-cylindrical bottom plate, and a top plate having a quartercylindrical portion concentric to said bottom plate and spaced therefrom and a planar portion connected to one end of said quarter-cylindrical portion, said side plates, bottom plate and quarter-cylindrical portion cooperating to form a first processing zone of limited volume, and said side plates, bottom plate and planar portion coopcrating to form a second processing zone of greater volume than said first processing zone hydraulically connected to said first zone; means for agitating the monobath solution in said second processing zone; and means for transporting a material to be processed through said first and second processing zones in succession.

References Cited in the file of this patent UNITED STATES PATENTS 2,614,927 Broughton et a1 Oct. 21, 1952 2,696,439 Levinos et a1 Dec. 7, 1954 2,712,977 Keggin July 12, 1955 2,747,479 Babcock et al May 29, 1956 2,762,281 Kleinstra Sept. 11, 1956 2,800,682 Dooley July 30, 1957 2,945,760 Ostergaard July 19, 1960 OTHER REFERENCES Newman: Seventy Years of Progress in Photographic- Monobaths, British J. of Photography, Jan. 23, 1959, pages 44-48 and 5 6. 

1. THE METHOD OF CONTINUOUSLY PROCESSING A STRIP OF EXPOSED LIGHT SENSITIVE MATERIAL BY DEVLOPING AND FIXING THE STRIP IN A SINGLE MONOBATH SOLUTIN COMPRISING THE STEPS OF: FILLING A TANK WITH A MONOBATH SOLUTION CONTAINING BOTH DEVELOPING AND FIXING INGREDIENTS IN PREDETERMINED PROPORTIONS IN WHICH THE DEVELOPING ACTION NORMALLY PREDOMINATES, AND DIVIDING THE SOLUTION INTO FIRST AND SECOND WELL DEFINED, HYDRAULICALLY CONNECTED PROCESSING ZONES HAVING THE SAME PREDETERMINED PROPORTIONS OF INGREDIENTS, IN WHICH THE SECOND ZONE CONTAINS A SUBSTANTIALLY GREATER PORTION OF THE VOLUMNE OF THE SOLUTION, CONTINUOUSLY AGITATING THE PORTION OF THE SOLUTION IN THE SECOND ZONE AT A CONTROLLED RATE SUFFICIENT TO CAUSE THE FIXING ACTION OF THE FIXING INGREDIENTS TO PREDOMINATE OVER THE DEVELOPING ACTION OF THE DEVELOPING INGREDIENTS IN THE SECOND ZONE, WHILE THE SOLUTION IN THE HYDRAULICALLY CONNECTED FIRST ZONE REMAINS IN A SUBSTANTIALLY QUIESCENT STATE WHEREIN THE NORMAL PREDOMINATION OF THE DEVELOPING ACTION IS RETAINED, AND CONTINUOUSLY TRANSPORTING THE EXPOSED STRIP AT A PREDETERMINED SPEED CONSECUTIVELY INTO TAND THROUGHSAID FIRST PROCESSING ZONE FOR DEVELOPMENT, THROUGH THE HYDRRAULIC CONNECTION, AND THEN INTO AND THROUGH SAID SECOND PROCESSING ZONE FOR FIXING.
 2. IN A PROCESSING MACHINE HAVING A MONOBATH SOLUTION CONTAINING BOTH DEVELOPING AND FIXING INGREDIENTS, THE COMBINATION COMPRISING: A TANK FOR SAID MONOBATH SOLUTION COMPRISING SIDE PLATES CONNECTED BY A SEMI-CYLINDRICAL BOTTOM PLATE, AND A TOP PLATE HAVING A QUARTERCYLINDRICAL PORTION CONCENTRIC TO SAID BOTTOM PLATE AND SPACED THEREFROM AND A PLANAR PORTION CONNECTED TO ONE END OF SAID QUARTER-CYLINDRICAL PORTION, SAID SIDE PLATES, BOTTOM PLATE AND QUARTER-CYLINDRICAL PORTION COOPERATING TO FORM A FIRST PROCESSING ZONE OF LIMITED VOLUME AND SAID SIDE PLATES, BOTTOM PLATE AND PLANAR PORTION COOPERATING TO FORM A SECOND PROCESSING ZONE OF GREATER VOLUME THAN SAID FIRST PROCESSING ZONE HYDRAULICALLY CONNECTED TO SAID FIRST ZONE; MEANS FOR AGITATING THE MONO BATH SOLUTION IN SAID SECOND PROCESSING ZONE; AND MEANS FOR TRANPORTING A MATERIAL TO BE PROCESSED THROUGH SAID FIRST AND SECOND PROCESSING ZONES IN SUCCESSION. 